Ottimizzazione fluidodinamica di una superficie portante per un catamarano da competizione.

L'obbiettivo della tesi è stato quello di determinare una configurazione ottimale di una superficie portante per un catamarano da competizione. E' stata sviluppata una procedura di ottimizzazione in ambiente modeFRONTIER, nel quale il ciclo viene definito sotto forma di diagramma di flusso. I nodi principali del diagramma che hanno richiesto un precedente sviluppo sono due: quello dove viene importato il modello geometrico e quello dove viene impostato il solutore aerodinamico. Per il primo è stato utilizzato il programma CATIA V5 nel quale sono stati definiti i parametri geometrici liberi da ottimizzare. Per quanto riguarda invece il solutore aerodinamico è stato impostato il software STARCCM+, che risolve le equazioni di Navier-Stokes in forma di Reynolds (RANS) per flussi turbolenti sui nodi di una griglia, ottenuta dalla discretizzazione del dominio di calcolo. Una volta determinata la configurazione ottimale dai risultati dell'ottimizzazione sono stati verificati i vincoli di ingombro imposti dai regolamenti della competizione. Questi hanno portato allo sviluppo di due nuove geometrie a partire da quella ottimizzata. Infine sono stati messi a confronto i risultati ottenuti dalle simulazioni fluidodinamiche delle tre configurazioni finali

Effects Of Position, Orientation, And Infiltrating Material On Three Dimensional Printing Models

This research defined and evaluated mechanical properties of prototypes created using a plaster based three-dimensional printing (3DP) system commercialized by Z Corporation. 3DP is one of the fastest growing forms of rapid prototyping. Till date, there is little or no information available on material properties of infiltrants used in 3DP. This research work evaluated and documented some of the useful information for 3DP users by determining the effect of build position, build orientation and infiltration materials on the strength of prototypes. The study was performed in three different phases to limit the processing variables and to arrive at definite conclusions on relationship between materials properties and process variables. All specimens were built on the Z Corporation Spectrum Z510. In Phase 1, effects of build location on specimen strength was studied. Phase 2 evaluated the influence of build orientation on specimen strength. System Three Clear Coat epoxy was used during both Phase 1 and 2 for infiltration. The same infiltrant was in both of these phases to limit variables. Using results of Phase 1 & 2, the effects of infiltrant material on tensile strength of prototypes was calculated in Phase 3. Seven different infiltrating materials were tested during Phase 3. These materials included 2 cyanoacrylates and 5 epoxies. The tensile strength, flexural strength, and density and porosity of the specimens were determined and correlated. In each phase six specimens were built for each test performed. Two consistent methods of infiltration were utilized to infiltrate cyanoacrylates and epoxies into the as-processed specimens. It was found that the orientation of the specimen has more of an impact on strength than position within the build platform. The layering build process of rapid prototyping creates a variance in strength depending on the build orientation. Specimens infiltrated with epoxy achieved much higher strength than the specimens infiltrated with cyanoacrylate. Cyanoacrylates may be a good choice in making color concept models; however they are not good candidate materials where strength requirement is important. The epoxies with lower viscosities demonstrated higher part strength among the materials tested